On my dreamlist for places I want to visit (in no particular order):
Australia-for herping and diving the GBR
Roatan-Diving then to the mainland for some south american herping
Fiji-Diving
New Zeland-to check out all the amazing crazy animals
Madagascar-for all the great herps and other animals.
Africa- for a traditional safari and to check out BP in their natural habitat
California kelp forests-diving
Everglades-herping
Those are all that I can think of right at this moment.